1. Field of the Invention
The present invention generally relates to printer color characterization and more particularly to determining printer color characterization data for an ink cartridge that can be used to control the color density generated by the ink cartridge.
2. Description of the Related Art
To generate a printer profile, the printer manufacturer begins by printing a color test chart with the color ink jet printer model of interest. The color test chart, which carries the characteristics of the color ink jet printer on which it is printed, generally contains color patches for each shade of the colors of interest. A color measurement device such as a spectrophotometer or a calorimeter measures the spectral distribution or intensity of each color patch on the color test chart and the data is provided to a computer system of the printer manufacturer.
Color analysis software on the computer system analyzes the color data by comparing the color data for each patch of the color test chart to the corresponding standard color data such as defined by CIE (Commission International de l'Eclairage or International Commission on Illumination) color standards. A printer profile is then built based on this analysis to compensate or correct for the differences between the test color data and the standard color data. Based on the color analysis, a transformation matrix or a multidimensional look-up table of the printer profile can convert any standard color data to output color data for the color ink jet printer. The printer profile may further include a linearization table to linearize the standard color data before and after the matrix transformation.
A printer profile takes parameters into account such as printing process, ink types and rendering intention (e.g., perceptual, relative colorimetric, saturation or absolute calorimetric). The standard format for printer profiles as well as other types of device color profiles is described in the International Color Consortium (ICC) Specification ICC.1:2001-12. In general, when a user selects to print an image, printer or imaging software on the computer system retrieves the printer profile from the color management system for the color ink jet printer and performs printer color correction for the image based on the profile.
The above approach to printer color correction does not take into account that an original color ink cartridge in a color ink jet printer will later be replaced by a new color ink cartridge, which itself can be replaced. Once a replacement color ink cartridge is used in the color ink jet printer, the printer profile generated with test color data when the color ink jet printer included the original color ink cartridge may not render consistent or perceptually uniform color for the color ink jet printer. A generic printer profile thus has been unreliable in rendering consistent color once the color ink jet printer includes a replacement color ink cartridge, with the result that images printed with replacement ink cartridges frequently do not appear the same as identical images that were previously printed using that printer.